This application requests funds for the purchase of a Laser Scanning Cytometer (LSC) for the Flow Cytometry Shared Resource of the CSHL Cancer Center (2P30CA45508-14). At its simplest level, the LSC can be described as a cross between a flow cytometer and an inverted imaging microscope. LSC technology employs up to three lasers to collect fluorescent and bright-field images from samples on microtitre plates, slides and Petri dishes. It permits single-cell quantification of macromolecules and detailed kinetic analyses not possible with traditional suspension flow cytometry. The LSC will thus provide an entirely new approach to CSHL researchers studying the regulation of gene expression, cancer, cell biology, and development, and there is understandably much interest among researchers at CSHL for obtaining this instrument. Cold Spring Harbor Laboratory has a reputation for cutting-edge research, but its physical isolation means that having instrumentation such as an LSC on campus is essential to the ongoing success of our research. The LSC will be housed in the recently renovated Flow Cytometry Facility, and integrated into the existing Flow Cytometry management and maintenance structure. Importantly, our exploitation of LSC will benefit greatly from the fact that the Flow Cytometry Shared Resource shares building space with the Microscopy Shared Resource-a natural location for an instrument of this kind, and one that will promote the full use and benefits of LSC to CSHL researchers.